In recent years, labels on which bar codes are printed have been made for attaching to commodities marked with no bar code with the intention of merchandise management utilizing bar codes. In order to make such labels, heat sensitive recording methods have been employed because they have been attained greater economy in both printer and recording paper.
On the other hand, the movement for constructing such a system as to perform various kinds of services and to direct the management utilizing informations input in ID cards by making the most of an electronic computer has gained force. Moreover, it has been tried to input desired informations in the form of bar codes into ID cards, then to read out through optical reader, and an increase in demand for the ID cards provided with portraits for identification with their respective bar codes through human eyes has been expected. In making the ID cards provided with bar codes, there have been employed various types of printers connected to the terminals of electronic computers, which are designed so as to accord with a recording method adopted, for example, a heat sensitive recording method, an electrostatic recording method, an electrophotographic recording method, and so on.
However, conventional recording methods have a problem that they cannot offer ID cards provided with bar codes, portraits, etc., and bar-code labels at both high speed and low price. In addition, bar-code labels made in accordance with conventional methods have a disadvantage that when exposed to dusts, oils and so on, or to water or some kind of solvent by experiencing such a condition as to be freezed, or so on, it frequently occurs that bar codes recorded on lables become dirty, fade away or get out of their shapes, and thereby it becomes difficult or impossible to read them with a bar-code reader. In case of a card provided with both a portrait and a bar code, the ID card of this type is used over a long period of time, and thereinto informations are input repeatedly. Further, character informations recorded therein, such as name, issue date, etc., must not be falsified. Accordingly, it is necessitated to cover not only a bar code but also the whole surface of recorded area with a thick film in making an ID card. Furthermore, form the standpoints of prevention of forgery and using by stealth, it is necessary to record a portrait, a bar code and so on in the form of integral unit so that the portrait cannot be replaced with another person's one. In order to settle this point, it is required to cover the recorded face with a transparent film, and thereby to protect the records including a bar code, etc. However, when a thick transparent film is used with the intention of giving satisfactory protection to the recorded surface, it becomes difficult to effect the recording through the transparent film. Consequently, the film must be superposed on the recorded surface, and made into a laminate. This procedure is troublesome.
Moreover, in order to laminate a film on a surface of the recording material such as bar-code labels or ID cards recorded with a bar code etc., it is necessary to use a lamination apparatus. Therefore, the intended bar-code labels and ID cards cannot be made inexpensively. In this respect also, the recording method which makes it feasible to record a bar code and other informations in the recording layer, which was previously covered with a transparent film as a protective layer, through the transparent film has been required.
As for the methods which have so far been employed for making bar-code labels and ID cards, for instance, a heat sensitive recording method made it necessary to use a thin transparent film in order to achieve the recording as the recording layer is covered with the transparent film. On the other hand, the recording of informations on the surface to be recorded through a transparent film was, in itself, impossible in the electrophotographic recording methods, the electrostatic recording methods, the inkjet recording methods, the heat sensitive transfer recording methods and so on which had been employed in conventional photoprinters, such as a laser beam printer, an LED printer, an OFT printer, an LCS printer utilizing liquid crystal shutters, and the like.
When a portrait, a bar code and character informations are intended to be recorded in an integral unit, as required of ID cards, the problems before us are as follows: Since resolutions required for clearly recording a portrait, a bar code and character informations are different from one another, and the resolving power depends, e.g., on the diameter of a thermal head or that of jetting ink in the heat sensitive recording method and the ink jet recording method, respectively, an expensive apparatus or a decrease in recording speed is required for clear recording of portraits and the like. After all, it was impossible to rapidly and cheaply record a portrait, a bar code, character informations and so on in the form of an integral unit.
As the results of concentrating our energies on solution of the above-described problems, it has now been found that even when a recording layer is covered with a thick transparent film, a bar code, characters, a portrait and so on can be recorded cheaply and rapidly by using a thermodevelopable photo-recording material provided with a thermodevelopable photo-recording layer containing a diazo compound and a coupler as primary components, and forming a temporary image utilizing as constituent units minute matrixes which come to be able to transmit light or come to be inable to transmit light when electric current is passed therethrough, and then exposing said photo-recording layer to light through said temporary image, followed by heating said recording material. Thus, we have achieved the present invention.